The present invention relates generally to rim-holding tire changers, and more particularly to a quick-change assembly that can be connected to the mount/dismount head so that different dismount heads can be quickly substituted, one for the other with the proper angle and orientation of the mount/dismount head prefixed to mate with the rim for which the mount/dismount head is designed.
On rim-holding type tire changers, the contoured tool head is the device that allows the tire to be removed from or installed on the rim without damaging the bead rubber of the tire. The contoured tool head is sometimes referred to as the mount/dismount head. The mount/dismount head is normally connected to the lower end of a bar that is attached to a swing-arm. The swing-arm rotates about a pivot point and allows the mount/dismount head to be brought into engagement with the rim or be removed from engagement from the rim. The bar is mounted on the swing-arm for movement vertically so that the alignment of the head with the rim can be easily achieved.
One rim-holding tire changer can be used to mount or dismount the tires for a variety of types of vehicles. It is not uncommon for such a changer to be used to mount and dismount the tires on the rims of automobiles, pick-up trucks, motorcycles, and the like. Further, with some automobile rims, the rims are quite decorative, made of polished chrome and the like and thus require a special mount/dismount head in order to avoid marring the surface of the rim.
There are several basic designs for supporting the mount/dismount head; some machines have a tower with horizontal and vertical sides. These machines assure that the head is always tangent and perpendicular to the center line of the rim. However, these types of machines are unpopular because of manufacturing costs and because the tool head is normally at a very awkward location, usually the twelve o'clock position relative to the operator.
The more popular type of tire changer design is the "swing-arm" style of machine. Manufacturing costs of such machines is usually less; further, the mount/dismount head is positioned at the three o'clock or four o'clock position relative to the operator, which is much easier for the operator to handle. Unfortunately, in the swing-arm style machine, the mount/dismount head does not track exactly a tangent line perpendicular to the rim center line on all rims, because of the wide variety of rim diameters that must be serviced. Usually six-inch to twelve-inch rims require one setting, rims of twelve inches to eighteen inches require another setting, and rims eighteen to twenty-two inches require yet another setting. Because the setting angle of the mount/dismount head must be changed depending upon the size of the rim that a tire is being mounted on, the speed of the operator in a high-volume operation is substantially reduced because the operator must reset the angle with each new size rim and changing the angle of the head is time-consuming. Further, when the operator needs to change from a regular metal mount/dismount head to a plastic mount/dismount head in order to prevent scratching of decorative rims, setting the angle of the mount/dismount head is time-consuming.
It would be appreciated by those skilled in the art of designing and manufacturing equipment used to change the tubeless tires mounted on the rims of cars, light trucks and other vehicles, that such equipment must perform quickly and efficiently in order to be competitive in the marketplace. Modest improvements in the industry can thus become significant.
The type of equipment for which Applicant's invention is designed is the swing-arm rim-holding tire changer. Examples of such equipment include the tire changers manufactured by Hennessy Industries, Inc., Applicant's Assignee and marketed under the trademarks COATS.TM. and AMMCO.TM., including the COATS.TM. Model 5030A, Model 5060A-E and Model 5060AX-EX. However, there are many manufacturers of such equipment, including FMC Corporation of Chicago, Ill.; Corghi of Correggio, Italy, and SICE of Correggio, Italy. Equipment of this type has been readily available and on the market for many years, is the subject matter of numerous patents and has been described in a variety of publications, bulletins and brochures, operating instructional manuals, and the like. One such machine is illustrated in the design patent issued to Applicant as coinventor in U.S. Design Pat. No. 293,916.
In the normal tire-changing procedure, the operator places a rim on the table of the rim-holding tire changer, secures the rim to the table, places a tire over the rim, mounts the tire on the rim by using the mount/dismount head to force the bead over the rim, and then fills the air chamber of the tire with air to inflate the tire. This procedure is described in detail in U.S. patent application Ser. No. 08/516,129, the substance of which is incorporated here and by reference, and which is assigned to the Assignee of the present invention.
A problem that exists with the prior devices is the fact that when a different size rim is placed on the table, the angle of the mount/dismount head to the perimeter of the rim will not be properly oriented. The present invention provides a simple, inexpensive modification to obviate the problems of the prior art.